After two days of labour
, swapping ram, DW, restore whith SD, reinstall OSX, tryed a lot of differents things and had always a lot of problems booting, blue screen, boot to Darwin etc
The last thing... the disk,even if the surface test was ok, i replaced the drive, format,and ...
Tiger installed whith no problem !!!
Ok for now, but for how long?
Thanks for your replys and help
GR